﻿namespace Grade
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Console.Write("请输入成绩：");
            int n = int.Parse(Console.ReadLine());
            string result = n >= 90 ? "A" : (n >= 60 ? "B" : "C");
            Console.WriteLine(result);
        }
    }
}
